Fused pyrrolocarbazoles display various pharmacological activities. For example, fused pyrrolocarbazoles are useful for treatment of neurological diseases or disorders, and some display antifungal, antimicrobial, or antitumor activity. In some cases this is accomplished by modulation of neurotrophic responses through effects on protein kinase activity (Berg et al., J. Biol. Chem. 267:13-16 (1992)). Fused carbazoles and their derivatives have been isolated from a various microorganisms, including S. staurosporeus, N. aerocoligenes, Actinomadura and Nocardiopsis sp, (Kase et al., Biochem. Biophys. Res. Commun. 142: 436-440, (1987)).
Specific fused pyrrolocarbazoles, such as indolocarbazoles, which have been characterized include the following: staurosporine and rebeccamycin (Moody et al., supra); K-252a, K-252b (Kase et al., supra); K-252c (also called staurosporine aglycon) (Moody et al., supra), K-252d and derivatives thereof (published Japanese patent applications 60-257652, 60-295172, 62-327858, 62-327859, and 60-295173). K-252a, K-252b, K-252c, and K-252d are insoluble in water (Nakanishi et al., J. Antibodies, 34:1066, (1986)).
In general, fused pyrrolocarbazoles display very low water solubility. Dry pharmaceutical preparations (dragees, tablets and capsules) of staurosporine derivatives that may contain polyethylene glycol and polyvinylpyrrolidone have been described in U.S. Pat. No. 5,093,330. Conventional pharmaceutical formulations that include indolocarbazoles are described in U.S. Pat. No. 5,043,335 and PCT publication No. WO 93/00909. Aqueous indolocarbazole compositions are described in U.S. Pat. No. 5,599,808.
Self-emulsifying drug delivery systems (“SEDDS”) have been developed for drugs that display very low water solubility but good oil solubility. See, e.g., Shah et al., International Journal of Pharmaceutics (Netherlands) 106:15-23, (1994). Despite their low water solubility, fused carbazoles are generally unsuited for SEDDS because of their low oil solubility.